There could have been much more than you thought in the cost of demo. 

And the minute I get back to Nashville, every single time, I head immediately to Demos'. :) I LOVE Nashville.

Just got to the point in the demo of this 1920s 1.5 story house, where I into the walls enough to see that this is a balloon framed house.

Does anyone have any guides to educational tools that they found helpful when demoing their first few investments?

If you are using unfinished flooring your base will be marked up from the sanders, edgers and you may get some unintentional poly splash when coating. also if there is existing hardwood that will be refinished cover it before you paint and careful with the demo guys removing carpet.

I actually ended up helping demo a bit and carrying sheetrock and supplies to the second floor. then we had a conversation about various things so it was a good experience

Its not cheap to have a property demoed in Detroit, Ex.  2100 sf , two story, between two existing homes will cost approx. 13k, without asbestos and lead remediation - it will take 60-90 days to get utilities terminated, and proper permits issued.

Get the ARB done during demo and still have a long time to get the windows done.  

Problem is demoing out plaster and lath is so time consuming and expensive, and then you have stud walls that need to be shimmed because they didn't bother making them straight when it was going to be plastered.

If you're flipping the property I'd demo and rebuild the floor to modern standards with new materials.